The objective of this research is to gain additional knowledge of basic cardiovascular physiology relative to dentistry. The ongoing projects involve: assessing methodology, establishing animal models for observing circulation following orthognathic surgery, evaluating factors which regulate the circulation, developing various theoretical models, and expanding on-line computer capabilities. More specifically, investigations will be carried out to study blood flow changes, the role of collateral circulation and related fundamental processes for restoring homeostasis following various experimental or surgical procedures. The isotope fractionation technique and the particle distribution method will provide quantitative values of blood flow to various tissues. These methods will be combined with others, such as fiberoptic densitometry to provide further description of the physiological processes. These projects may delineate techniques which can have clinical application.